The Civil War Artillery Message Board

The birdcage half of the shell was covered with a papermachie material.This would (in therory) expand when fired to engage the rifling of the cannon.

This sabot material would then disintergrate from the muzzle blast upon exiting the barrel. Or if still on the shell,time and exposure to the elements,would rot it away exposing the unique iron construction.

It is very possible that under the right conditions, that the bits of smoldering papermachie could have been the cause of fires that occured on various battlefields.